1983 Volume 32 Issue 12 Pages 602-608
Cylindrical concrete and stainless steel blocks were irradiated one week by the cyclotron of Institute for Nuclear Study of University of Tokyo. Their gamma-ray activities were measured by a high-purity Ge (HPGe) detector and simultaneously the residual exposure rates were measured by the GM survey-meter. Radionuclides and their gamma-ray activities were obtained by dividing the peak counts of the measured pulse height spectra by the peak efficiencies. For this purpose, the HP Ge detector having known sensitive region in good accuracy was used, and its peak efficiency to these cylindrical sources was calculated by the PEAK Monte Carlo code including the self-absorption correction.
The residual exposure rates were obtained from the simple analytical calculation by using these gamma-ray activities uniformly distributed in the concrete and stainless steel blocks. The calculated exposure rates showed very good agreement with those measured by the GM survey-meter. From this comparison, the relationship between gamma-ray activities and residual exposure rates were evaluated in good accuracy for these volume samples.